GM is replacing the old engine with the same engine used in Verano Turbo and Buick Regal GS and putting this 2.0 liter turbocharged engine in the Chevy is a lot easier because it is based similarly to the Delta II platform that Chevy Volt uses. 
The new Chevy Volt will have an improved performance with 250 hp as the new 2.0 liter turbo is coupled to more powerful electric motor. The new powerful engine will generate more power electricity to the electric motor as well as for the batteries.
In addition, General Motors is on the planning stage of making a Cadillac version using the Volt engine. The engine system is called as ELR promising to make the car has a sportier feel on any driving mood. Gm is being optional ;if the engine does not work on Volts, then ELR will have it.
Gm is not linking out any official statement for the possibility of engine swap however observers are optimistic that information may come up even before 2014 comes near and for the 2014 model launch.
The talks of engine upgrade sprung out after Volt 2013 model underwent a host of changes. On top of this, Gm has been open to the improvement of the Volt in order to keep its price on the high range. With people becoming more price and fuel- efficiency conscious, with all the improvements and upgrades, GM hopes that to make Chevy still the car people dare to buy.